1. Field of the Invention
The invention relates to glass manufacturing. More specifically, it relates to chemical treatment of glass for strengthening the microcrack structure of the surface thereof. A surface active agent such as a fatty acid is applied in combination with a catalyst or seeding agent and is chemisorbed on the surface of the glass.
2. Description of the Prior Art
Copending application Ser. No. 648,329, now U.S. Pat. No. 4,039,310 to Sipe and Ida, incorporated by reference herein, discloses a method for strengthening glass against failure under tension by chemisorbing fatty acids in the microcrack structure of the surface of the glass. This method calls for the fatty acid to be applied to the surface of the glass at temperatures from approximately 371.degree. C. to the decomposition temperature of the fatty acid, perhaps 871.degree. C. Experimental results suggested that application of the acids at significantly lower temperatures would fail to produce the observed strengthening.
Some support for the belief that fatty acids do not produce strengthening when applied at lower temperatures is found in U.S. Pat. No. 3,876,410 to Scholes, which teaches that fatty acid applied at such lower temperatures aids in producing a scratch resistant glass surface, but little improvement in the total strength of the glass was observed.
Fatty acids and their derivatives are known for other uses in connection with glass making, such as being a mold lubricant as taught in U.S. Pat. No. 3,495,962 to Norton; being a quenching agent for metalizing a glass surface as taught in U.S. Pat. No. 3,508,894 to Torok; or working in combination with titaniun esters to render glass scratch resistant as taught in U.S. Pat. No. 3,387,994 to Dunten et al.